Make an Ear Piercing Sonic Grenade

Sonic grenades Yep. Pull the pin, and instead of exploding, these bad boys emit an ear piercing shriek that is guaranteed to wake the dead (or a hungover roommate, little brother, or co-worker). They’re also great for Airsoft or Laser Tag battles.Ã‚ All you gotta do is modify a couple of standard alarms to “explode” when the pin is pulled.Ã‚ This is a rather simple, fun project that can be completed within a short amount of time.

Above, the standard version is on the left, with a blinking LED that lets you know the nade is hot.Ã‚ On the right is a camoflauge version that you can conceal in plain sight (just conceal the pin, of course).

If the pin is pulled while the SAFETY is not pressed, the LED begins flashing immediately and the 5 second countdown begins right away. When the grenade “goes off” after the 5 second fuse, the alarm sounds for 5 seconds after which the alarm turns off. After 60 seconds (and every 10 seconds thereafter) the LED will blink and the alarm will “chirp” briefly until the pin is replaced.